This invention relates to railway safety equipment, namely, derails which are commonly used for derailing railed vehicles including locomotives, railroad cars and the like which may be undesirably moving along railroad tracks normally at a relatively low speed.
There are many types of derails known in the railroad industry which have been used for many years. Certain types of derails are substantially permanently fixed to one rail of a pair of railroad track rails and various methods may be used to move the derail between an operative position and an inoperative position. Some derails are relatively light in weight so as to be portable and some are not movable between operative and inoperative positions.
As disclosed in the related application U.S. Publication 2010/0051757, the railway industry historically requires that the highest point of a derail was not to be more than four inches measured from the top of the rail upon which the derail was affixed. The reason for this requirement was that the pilot must be allowed to have cleared the highest point of the derail so that a heavy locomotive pilot (also known as a “cow catcher”) did not sweep, push or knock off the entire derail when the locomotive was undesirably moving at a relatively low speed, possibly up to ten miles per hour. In the event the derail is dislocated out of the operative derail position by the pilot, the derail becomes ineffective and the undesirably moving locomotive may cause serious damage to other locomotives, railway cars or even cause serious injury or death to workers in the area.
Relatively recently the railway industry changed its standards to require that certain derails could not have its highest point be more than three inches above the upper surface of the railroad rail upon which the derail is affixed. Existing derails higher than three inches above the rail can now be unsafe to use in a railroad track area where a heavy locomotive's pilot could dislocate the derail track upon from which it is mounted before the lead wheel of the undesirably moving locomotive could be derailed by the derail. This situation would cause the undesirably moving locomotive to continue moving unsafely rather than allowing the derail to remain in place and cause a safe derailment of the locomotive by engaging the lead wheel of the locomotive.
While the low profile derail of the above mentioned U.S. Publication is very effective, the disadvantages of a derail of the disclosed type is that a one ended deflecting bar is only designed to derail a locomotive or other moving railway car going in only one direction as shown in FIGS. 1 and 3 of the above publication. It is known in the railway industry to provide double ended derails as shown, for example, in FIGS. 9-11 of U.S. Pat. No. 7,549,611, and also in U.S. Pat. No. 6,202,564 as well as in other patents. Such derails may be used to derail a vehicle, including a locomotive, in two directions. In such derails, however, the derail must be moved to another section of the rail for an oppositely moving locomotive since such derails are subject to being longitudinally pushed along the track upon where it has been mounted because there is no foolproof provision to stop such longitudinal movement of the derail along the track. Therefore, known double ended derails are useful to effectively derail any railway car or locomotive but they cannot be left in the same spot on the tract, that is, they must be repositioned to cause a safe derailment for an oppositely moving car or locomotive.
In addition to the desirability of providing a double ended derail assembly to be kept in the same place on a track, regardless of the direction of movement of a car or locomotive, a double ended is desirably used so that a locomotive moving in one direction or another or other railway may be derailed by the derail when the locomotive is undesirably moving along the track in either direction. Such a derail does not need to be repositioned as has been generally required in prior art double ended derails. It is also desirable to provide a low profile derail assembly such as shown in the above Publication.
In the derail industry, it is well known that spaced rails of a railway track can vary significantly in height. For example, in the case of a 75 pound nominal weight per yard of a steel rail, the rail could have an overall height of as high as 4 15/16 inches while another steel rail may have a nominal weight of 136 pounds per yard of length and could have a height of 7 5/16 inches. In other words, there can be more than a two inch difference between the heights of commonly used rails used in the railroad industry.
In addition, commonly known and used transverse, usually wooden, railroad ties which are secured to the rails of a railroad track also vary in lateral width ranging from as wide 9¼ inches maximum (nominal width of nine inches) down to a width of 7 3/16 inches (nominal width of seven inches), thereby having as much as about two inches of difference in width between commonly used railroad ties. It is desirable to provide a derail which may be secured to a tie, regardless of the tie's width.
Particularly in the case of derails that are low profile (less than 3 inches above the top of a rail) to avoid being moved out of the operative derail position by the pilot of a moving locomotive, a derail assembly of the low profile type is desirable to be very securely mounted both to the rail and a tie in the area being used so as to be effective in accomplishing the desired derailment of the undesirably moving locomotive, as well as other undesirably moving railway cars.